A wireless communications system conventionally uses intermittent reception to reduce power consumption of a mobile station (see, e.g., Japanese Laid-Open Patent Publication No. 2004-128949). Discontinuous reception (DRX) is defined as an intermittent reception mode by the 3rd Generation Partnership Project (3GPP) (see, e.g., 3GPP TS36.321, “Medium Access Control (MAC) Protocol Specification”, V10.4.0, Release 10, December 2011; 3GPP TS36.133, “Requirements for support of radio resource management”, V10.6.0, Release 10, March 2012; and 3GPP TS36.213, “Physical layer procedures”, V10.4.0, Release 10, December 2011). The use of DRX is associated with configuration of an interval requiring monitoring of a downlink control signal (referred to as an ON-interval for convenience) and an interval not requiring monitoring of a downlink control signal (referred to as an OFF-interval for convenience).